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OBC DIVISION B · PART 9 · SECTION 9.35 — GARAGES AND CARPORTS

What is the difference between a carport and a garage under the Ontario Building Code?

A carport must remain substantially open, generally on at least two sides; otherwise the Code treats it as a garage, triggering garage rules such as gas-proofing at the dwelling and different foundation and enclosure requirements. Openness is what preserves carport relaxations.

Code reference
The Code distinguishes carports from garages by their openness: a roofed vehicle shelter open to the required degree on its sides is regulated as a carport, relying on natural airflow to disperse exhaust, while a shelter enclosed beyond that threshold is deemed a garage and must meet garage provisions, including separation from the dwelling and drainage and foundation rules.
OBC Division B, Subsection 9.35.1.

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

The classification has teeth because carports skip the airtight separation and some enclosure requirements on the theory that fumes blow away. The common trap is incremental enclosure: an owner adds a wall for storage or wind protection, and the open carport quietly becomes a non-compliant garage lacking gas-proofing at the house wall. Before infilling carport sides or adding a door, check both the OBC implications and zoning, since parking and setback rules often differ for enclosed structures. Floor drainage and surface requirements also shift with the classification.

Plain language

A carport is basically a roof with open sides; close in those sides and, in the code's eyes, you have built a garage. That changes the rules, especially the airtight sealing needed where it touches your house.

Related questions

What are the foundation and floor slab requirements for garages in Ontario?What gas-proofing is required between an attached garage and the house in Ontario?

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.